What are TMDCs?
Transition metal dichalcogenides (TMDCs) are a new family of 2D nanosheets typically in the form of MX2 where M is the transition metal and X is the chalcogen [54,62,68].
What is the meaning of dichalcogenides?
Filters. (inorganic chemistry) Any chalcogenide containing two atoms of chalcogen per molecule or unit cell; any compound containing two different chalcogens.
What is spin valley coupling?
The considerable spin splitting at these valleys is induced by the intrinsic inversion symmetry breaking and the strong SOC effect, which leads to potential spin–valley coupling. The calculated Berry curvature with the same magnitude but opposite signs at valleys of K and K′ confirms their inequivalence.
What is Janus transition metal Dichalcogenides?
Abstract. Janus transition metal dichalcogenides (TMDs) lose the horizontal mirror symmetry of ordinary TMDs, leading to the emergence of additional features, such as native piezoelectricity, Rashba effect, and enhanced catalytic activity.
What are transition metal chalcogenides?
Transition metal chalcogenides are considered as emerging candidates due to their unique physical and chemical properties and are being researched for use in lithium-ion batteries, solar cells, hydrogen evolution, and photocatalytic degradation due to their indirect bandgaps, optoelectronic behavior, and stability.
What is Spin Valley?
In addition to spin, charge carriers in TMDs exhibit a “valley” degree of freedom, which behaves like a pseudospin. The two valleys can be optically addressed using circularly polarized light, opening up exciting possibilities for “valleytronics”.
What is Janus monolayer?
Janus monolayers are 2D semiconducting materials in which a layer of metal atoms is sandwiched between layers of two different chalcogen, halogen, or pnictogen atoms. These materials have a finite out-of-plane dipole moment, which causes a difference in the electrostatic potential on the two sides of the layer.
What is a valley in physics?
The “valley” in valleytronics refers to two dips that appear in plots of a solid’s energy bands at different electron momenta. By putting all the electrons into one valley or the other, those two dips could be used to represent the two values of bits (0 and 1) in information applications.
What is valley splitting?
The valley exciton splitting, on the other hand, is defined as the difference between the exciton transition energies of K and K′ valleys. Its sign is dependent on the relative shift of the conduction and valence bands in the two valleys.
What is the difference between alkali and alkaline metals?
Alkaline earth metals are the elements in the group 2. Both have basic properties. When added to water, both can form solutions having higher pH values (>pH). The main difference between alkali and alkaline is that alkali metals have one valence electron whereas alkaline earth metals have two valence electrons.
What is the formula for a transition metal dichalcogenide?
Transition metal dichalcogenides are considered as one of the 2D graphene analogues (1). The standard structural formula of TMDCs is MX 2, where M represents a transition metal element (e.g., titanium, molybdenum, tungsten, and niobium) and X denotes to a chalcogen (1).
How are transition metal dichalcogenides similar to graphene?
TMDCs are 2D nanomaterials consist of a monolayer of transition metal atoms sandwiched (X-M-X) between two layers of chalcogen atoms (usually selenium, sulfur, or telluride) in a hexagonal lattice (2). Transition metal dichalcogenides are considered as one of the 2D graphene analogues (1).
How are transition metal dichalcogenide monolayers produced in bulk?
Exfoliation is a top down approach. In the bulk form, TMDs are crystals made of layers, which are coupled by Van-der-Waals forces. These interactions are weaker than the chemical bonds between the Mo and S in MoS 2, for example. So TMD monolayers can be produced by micromechanical cleavage, just as graphene.
What are quantum dots in transition metal dichalcogenide?
The unique electronic, physical and chemical properties of nanostructured transition metal dichalcogenide (TMD) materials have received great attention, specifically, with the decrease of size to several nanometers, particles named TMD quantum dots (QDs).